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Alphanumeric Line Loss Factor Class Ids

v 3.0

Alphanumeric Line Loss Factor Class IDS

Guidance Note

Who should read this guidance

CP1434 ‘Amend the three digit numeric Line Loss Factor Class (LLFC) Id to an Alphanumeric LLFC Id’ will be implemented on 30 June 2016 as part of the June 2016 Release. The background to CP1434 is available on the CP1434 webpage.

This guidance is for Licensed Distribution System Operators (LDSOs), Suppliers, Supplier Agents and any other market participants and information system developers who are interested in the change. It sets out the allowable LLFC Id formats, timescales for introducing alphanumeric LLFC Ids and some of the key implications in terms of validation, data flows and testing.

What LLFC Ids will be allowable once CP1434 is implemented?

As part of the June 2016 Release, the definition of the Line Loss Factor Class Id (J0147) data item in the Data Transfer Catalogue (DTC) will change from three-digit integer to three-character alphanumeric. The relevant change under the Retail Energy Code (REC) is DTC CP 3472 ‘Amending the LLFC ID to an alphanumeric format’.

The data item will be variable in length, allowing up to three characters. Valid characters are the digits 0 to 9 and upper case letters other than I and O (to avoid confusion with 1 and 0). The following characters are not allowed:

    • Leading zeroes (so any codes beginning 0 or 00, including 000)

    • Lower case letters

    • The letters I and O (as above) and

    • Special characters, including spaces.

Why has the LLFC Id been defined as variable rather than fixed length?

At the time of writing there are about 12.7 million Metering Points (about 40% of the total) that are assigned to single or two digit LLFC Ids (i.e. in the range 1 to 99). Using a fixed length code would mean having to set up new LLFC Ids and reassign all these Metering Points.

How will the existing single and two digit LLFC Ids be represented?

LLFC Id 1 will become LLFC Id ‘1’. Please note that this guidance adopts the convention of expressing character values in single quotation marks. So in a typical pipe-delimited industry flow, this will appear as |1|, just as the integer value appeared as |1|.

Does this mean that LLFC Ids are not padded with leading zeroes?

It does for Settlement purposes. LLFC Id ‘1’ will be held in Market Domain Data (MDD) as ‘1’ and will be sent on industry flows as ‘1’. However, there is a requirement in Schedule 5 1(e) of the REC that:

“when printing these values [including LLFC Id] in a Supply Number, full physical length of these data items will be used. This will require the use of leading zeroes for any value whose length is less than total length for that data item defined in the DTC”.

This applies for integer LLFC Ids (e.g. LLFC Id 1 is printed on customer bills as ‘001’, 12 as ‘012’) and will continue to apply for alphanumeric LLFC Ids (e.g. LLFC Id ‘1’ will be printed as ‘001’, ‘12’ as ‘012’).

Does this apply to codes that use letters as well as those that only contain numbers?

Yes, the REC requirement applies to any values that are shorter than the maximum length of the data item. So an LLFC Id of ‘A’ would be stored in MDD as ‘A’, sent across the DTN as ‘A’, but printed on customer bills as ‘00A’. ‘AB’ would appear on customer bills as ‘0AB’, ‘5C’ as ‘05C’.

Although padding ‘A’ to ‘00A’ appears less intuitive than padding ‘1’ to ‘001’, our understanding is that those LDSOs who are running out of numeric LLFC Ids will not be using single or two character codes in the shorter term. CP1434 increases the number of available codes from 999 to 39,303 per LDSO. Avoiding the use of single and two character codes that contain letters still leaves 38,247 codes.

In general, we would advise against LDSOs selecting LLFC Ids that could cause confusion e.g. ‘LLF’, ‘TEN’ or S5S’.

Will we see alphanumeric LLFC Ids on the 30 June Implementation Date?

New LLFC Ids are subject to the usual MDD process. We cannot send alphanumeric LLFC Ids on the Market Domain Data Complete Set (D0169) and Market Domain Data Incremental Set (D0170) flows until the first publish date after 30 June 2016. This is scheduled for 13 July (with a go live date of 20 July). The deadline for raising MDD Change Requests for this release is 9 June. This is before the new MDD entity forms for alphanumeric LLFC Ids go live (as these are also subject to the 30 June Implementation Date). If LDSOs need alphanumeric LLFC Ids for 20 July, we will be able to accommodate requests on old (or redlined) entity forms.

Although there will be no new LLFC Ids containing letters until 13 July at the earliest, existing integer LLFC Ids will be alphanumeric from 30 June.

How will LLFC Ids be validated against the format rules?

We expect LDSOs to follow the formatting rules when requesting new LLFC Ids. Elexon will carry out checks as part of the Supplier Volume Allocation Group (SVG) approval process. We input LLFC Ids manually to the Market Domain Data Manager (MDDM) system, so there is a risk a user will read ‘A06’ as ‘AO6’. Input values will therefore be validated against the formatting rules. Similarly, we will validate LLFC Ids in the Line Loss Factor Data File (D0265) against the formatting rules. Once we have created valid LLFC Ids and associated LLFs, we don’t need to perform any further format validation. All subsequent validation will be against MDD.

Do market participants need to perform format validation?

No, market participants should continue to validate LLFC Ids against MDD. All MDD will have been format checked, so there should be no need to carry out further format checking as a result of CP1434.

Will incorrectly formatted LLFC Ids in aggregation files be rejected by central systems?

No. The Supplier Volume Allocation Agent (SVAA) will validate input data on the following flows against MDD in the normal way:

    • Aggregated Half Hour Data File (D0040)

    • Supplier Purchase Matrix File (D0041)

    • BM Unit Aggregated Half Hour Data File (D0298)

    • Mapping Data for Aggregated Metering System (P0239)

The Non Half Hourly Data Aggregator (NHHDA) software will validate the Instruction(s) to Non Half Hourly or Half Hourly Data Aggregator (D0209) flow against MDD in the normal way.

If a D0040, D0041 or D0298 flow contains an incorrectly formatted LLFC Id, the SVAA will process the consumption data, but will apply a default LLF of 1.000 (i.e. will not apply any line losses). This is the same process used for any LLFC Id that does not exist in MDD.

Which data flows are affected?

The table below shows all the Data Flows that include the LLFC Id. Please note that Elexon will test all flows where the source and recipient is the MDDM, SVAA or NHHDA. For example, we will test that the SVAA can generate a D0030 flow that includes alphanumeric LLFC Ids, but LDSOs and Suppliers will need to test that their systems can process a D0030 flow containing alphanumeric LLFC Ids.

Data Flow

Flow Name




Aggregated DUoS Report


LDSO, Supplier


Aggregated Half Hour Data File


SVAA, Supplier


Supplier Purchase Matrix Data File


SVAA, Supplier


Supplier - Supplier Purchase Matrix Report




Notification from MPAS of Changed Metering Point Details




Notification of Removal of a Registration Objection




Notification of Distributor Changes to Metering Point Details




Selective or Full Refresh of MPAS Details




Instruction(s) to Non Half Hourly or Half Hourly Data Aggregator




Confirmation of the Registration of a Metering Point




Supercustomer DUoS Daily Statement




Line Loss Factor Data File


SVAA, HHDA, Supplier


Market Domain Data Complete Set


SVAA, all participants


Market Domain Data Incremental Set


SVAA, all participants


BM Unit Aggregated Half Hour Data File


SVAA, Supplier


Notification of Old Supplier Information


Supplier, NHHDC


Non Half Hourly Embedded Network DUoS Report




Aggregated Disconnected DUoS Report


LDSO, Supplier


Supplier - Supplier Disconnection Matrix Report




Aggregated Embedded Network Disconnected DUoS Report




Disconnection Purchase Matrix Data File


SVAA, Supplier


HH Unmetered Supply Certificate

Supplier, UMSO

USMO, Supplier, customer


Request Creation of UMS Skeleton SMRS Record




NHH Unmetered Supply Certificate


Customer, Supplier


EAC Data to Distributor Report




Mapping Data for HH Aggregated Metering System



Need more information

For more information please contact the BSC Service Desk or call 0370 010 6950.

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